FFMPEG conversion commands

First of all we need to see how to install ffmpeg on a debian based system.

$ sudo add-apt-repository ppa:jon-severinsson/ffmpeg
$ sudo apt-get update
$ sudo apt-get install ffmpeg

This article describes some basic audio format conversions using ffmpeg utility. All ffmpeg format conversion commands use default ffmpeg setting. User should alter below commands to increase or decrease audio quality with additional ffmpeg options.

How to play files from command line?

To play wav files try to see if sox is installed on the system using command man sox to see a detailed explanation for the sox command. It will display information if the sox is installed
type in play to play the audio file of wav format.

To play mp3 from command line using this command.
sudo apt-get install mpg123
sudo apt-get install libsox-fmt-mp3

Then type in play

1.1. WAV – Waveform Audio File Format

1.1.1. wav to mp3

Convert wav to mp3 with ffmpeg:

ffmpeg -i audio.wav -acodec libmp3lame audio.mp3
 
to control the quality see this page Encodemp3
ffmpeg -i audio.wav -codec:a libmp3lame -qscale:a 0 audio.mp3
 
qscale is the one that controls the quality of the audio file 

1.1.2. wav to ogg

Convert wav to ogg with ffmpeg:

ffmpeg -i audio.wav  -acodec libvorbis audio.ogg

1.1.3. wav to aac

Convert wav to acc with ffmpeg:

ffmpeg -i audio.wav  -acodec libfaac audio.aac

1.1.4. wav to ac3

Convert wav to ac3 with ffmpeg:

ffmpeg -i audio.wav -acodec ac3 audio.mp3

1.2. OGG – Free, open standard container

1.2.1. ogg to mp3

Convert ogg to mp3 with ffmpeg:

ffmpeg -i audio.ogg -acodec libmp3lame audio.mp3

1.2.2. ogg to wav

Convert ogg to wav with ffmpeg:

ffmpeg -i audio.ogg audio.wav

1.2.3. ogg to aac

Convert ogg to aac with ffmpeg:

ffmpeg -i audio.ogg  -acodec libfaac audio.aac

1.2.4. ogg to ac3

Convert ogg to ac3 with ffmpeg:

ffmpeg -i audio.ogg -acodec ac3 audio.ac3

1.3. AC3 – Acoustic Coder 3

1.3.1. ac3 to mp3

Convert ac3 to mp3 with ffmpeg:

ffmpeg -i audio.ac3 -acodec libmp3lame audio.mp3

1.3.2. ac3 to wav

Convert ac3 to wav with ffmpeg:

ffmpeg -i audio.ac3 audio.wav

1.3.3. ac3 to aac

Convert ac3 to aac with ffmpeg:

ffmpeg -i audio.ac3  -acodec libfaac audio.aac

1.3.4. ac3 to ogg

Convert ac3 to ogg with ffmpeg:

ffmpeg -i audio.ac3 -acodec libvorbis audio.ogg

1.4. AAC – Advanced Audio Coding

1.4.1. aac to mp3

Convert aac to mp3 with ffmpeg:

ffmpeg -i audio.aac -acodec libmp3lame audio.mp3

1.4.2. aac to wav

Convert aac to wav with ffmpeg:

ffmpeg -i audio.aac audio.wav

1.4.3. aac to ac3

Convert aac to ac3 with ffmpeg:

ffmpeg -i audio.aac  -acodec ac3 audio.ac3

1.4.4. aac to ogg

Convert aac to ogg with ffmpeg:

ffmpeg -i audio.aac -libvorbis audio.ogg
 
FOR VIDEO Conversion commands 
 

1. Cut video file into a smaller clip You can use the time offset parameter (-ss) to specify the start time stamp in HH:MM:SS.ms format while the -t parameter is for specifying the actual duration of the clip in seconds.

ffmpeg -i input.mp4 -ss 00:00:50.0 -codec copy -t 20 output.mp4

2. Split a video into multiple parts

If you want to split a large video into multiple smaller clips without re-encoding, ffmpeg can help. This command will split the source video into 2 parts – one ending at 50s from the start and the other beginning at 50s and ending at the end of the input video.

ffmpeg -i video.mp4 -t 00:00:50 -c copy small-1.mp4 -ss 00:00:50 -codec copy small-2.mp4

3. Convert video from one format to another

You can use the -vcodec parameter to specify the encoding format to be used for the output video. Encoding a video takes time but you can speed up the process by forcing a preset though it would degrade the quality of the output video.

ffmpeg -i youtube.flv -c:v libx264 filename.mp4

ffmpeg -i video.wmv -c:v libx264 -preset ultrafast video.mp4

4. Join (concatenate) video files

If you have multiple audio or video files encoded with the same codecs, you can join them into a single file using FFmpeg. Create a input file with a list of all source files that you wish to concatenate and then run this command.

ffmpeg -f concat -i file-list.txt -c copy output.mp4

5. Mute a video (Remove the audio component)

Use the -an parameter to disable the audio portion of a video stream.

ffmpeg -i video.mp4 -an mute-video.mp4

6. Extract the audio from video

The -vn switch extracts the audio portion from a video and we are using the -ab switch to save the audio as a 256kbps MP3 audio file.

ffmpeg -i video.mp4 -vn -ab 256 audio.mp3

7. Convert a video into animated GIF

FFmpeg is an excellent tool for converting videos into animated GIFs and the quality isn’t bad either. Use the scale filter to specify the width of the GIF, the -t parameter specific the duration while -r specifies the frame rate (fps).

ffmpeg -i video.mp4 -vf scale=500:-1 -t 10 -r 10 image.gif

8. Extract image frames from a video

This command will extract the video frame at the 15s mark and saves it as a 800px wide JPEG image. You can also use the -s switch (like -s 400×300) to specify the exact dimensions of the image file though it will probably create a stretched image if the image size doesn’t follow the aspect ratio of the original video file.

ffmpeg -ss 00:00:15 -i video.mp4 -vf scale=800:-1 -vframes 1 image.jpg

9. Convert Video into Images

You can use FFmpeg to automatically extract image frames from a video every ‘n’ seconds and the images are saved in a sequence. This command saves image frame after every 4 seconds.

ffmpeg -i movie.mp4 -r 0.25 frames_%04d.png

10. Merge an audio and video file

You can also specify the -shortest switch to finish the encoding when the shortest clip ends.

ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a aac -strict experimental output.mp4

ffmpeg -i video.mp4 -i audio.mp3 -c:v copy -c:a aac -strict experimental -shortest output.mp4

11. Resize a video

Use the size (-s) switch with ffmpeg to resize a video while maintaining the aspect ratio.

ffmpeg -i input.mp4 -s 480x320 -c:a copy output.mp4

12. Create video slideshow from images

This command creates a video slideshow using a series of images that are named as img001.png, img002.png, etc. Each image will have a duration of 5 seconds (-r 1/5).

ffmpeg -r 1/5 -i img%03d.png -c:v libx264 -r 30 -pix_fmt yuv420p slideshow.mp4

13. Add a poster image to audio

You can add a cover image to an audio file and the length of the output video will be the same as that of the input audio stream. This may come handy for uploading MP3s to YouTube.

ffmpeg -loop 1 -i image.jpg -i audio.mp3 -c:v libx264 -c:a aac -strict experimental -b:a 192k -shortest output.mp4

14. Convert a single image into a video

Use the -t parameter to specify the duration of the video.

ffmpeg -loop 1 -i image.png -c:v libx264 -t 30 -pix_fmt yuv420p video.mp4

15. Add subtitles to a movie

This will take the subtitles from the .srt file. FFmpeg can decode most common subtitle formats.

ffmpeg -i movie.mp4 -i subtitles.srt -map 0 -map 1 -c copy -c:v libx264 -crf 23 -preset veryfast output.mkv

16. Crop an audio file

This will create a 30 second audio file starting at 90 seconds from the original audio file without transcoding.

ffmpeg -ss 00:01:30 -t 30 -acodec copy -i inputfile.mp3 outputfile.mp3

17. Change the audio volume

You can use the volume filter to alter the volume of a media file using FFmpeg. This command will half the volume of the audio file.

ffmpeg -i input.wav -af 'volume=0.5' output.wav

18. Rotate a video

This command will rotate a video clip 90° clockwise. You can set transpose to 2 to rotate the video 90° anti-clockwise.

ffmpeg -i input.mp4 -filter:v 'transpose=1' rotated-video.mp4

This will rotate the video 180° counter-clockwise.

ffmpeg -i input.mp4 -filter:v 'transpose=2,transpose=2' rotated-video.mp4

19. Speed up or Slow down the video

You can change the speed of your video using the setpts (set presentation time stamp) filter of FFmpeg. This command will make the video 8x (1/8) faster or use setpts=4*PTS to make the video 4x slower.

ffmpeg -i input.mp4 -filter:v "setpts=0.125*PTS" output.mp4

20. Speed up or Slow down the audio

For changing the speed of audio, use the atempo audio filter. This command will double the speed of audio. You can use any value between 0.5 and 2.0 for audio.

ffmpeg -i input.mkv -filter:a "atempo=2.0" -vn output.mkv
 
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